Refrigeration cycle apparatus and refrigerator including the same

ABSTRACT

The present disclosure relates to a refrigeration cycle apparatus including an ejector capable of significantly increasing the pressure of sucked refrigerant and flowing out the refrigerant having the increased pressure toward a compressor. The ejector  100  includes a drive refrigerant inlet  111  to allow a first refrigerant evaporated in a first evaporator to be introduced, a suction refrigerant inlet  121  to allow a second refrigerant evaporated in a second evaporator to be introduced, a joining portion  131  to join the first refrigerant introduced from the drive refrigerant inlet  111  and the second refrigerant introduced from the suction refrigerant inlet  121 , a nozzle neck portion  113  to throttle a flow passage of the first refrigerant introduced from the drive refrigerant inlet  111 , and a nozzle diffuser portion  114  including a cylindrical or conical flow passage upstream of the joining portion  131  to allow the first refrigerant that has passed through the nozzle neck portion  113  to pass therethrough, and an inner angle α of the nozzle diffuser portion  114  in a plane passing through a center line C is 0° or more and 12° or less.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 National Stage of International Application No. PCT/KR2018/007723, filed Jul. 6, 2018, which claims priority to Japanese Patent Application No. 2017-133732, filed Jul. 7, 2017, and Japanese Patent Application No. 2018-115443, filed Jun. 18, 2018, the disclosures of which are herein incorporated by reference in their entirety.

BACKGROUND 1. Field

The present disclosure relates to a refrigeration cycle apparatus.

2. Description of Related Art

The present disclosure relates to a refrigeration cycle apparatus for a refrigerator for cooling a plurality of cooling spaces by a refrigeration cycle including an ejector.

As an example, a cooling system disclosed in patent literature JP 2009-236330 A is configured as follows. That is, the cooling system includes a compressor for compressing a refrigerant, a condenser for condensing the compressed refrigerant through cooling, a plurality of evaporators set at different pressures in combination with each expansion valve expanding the refrigerant delivered from the condenser, and an ejector disposed at a joining point of the refrigerants flowing out of the plurality of evaporators and configured to pressurize the refrigerant introduced from the evaporator set to a low pressure by the refrigerant introduced from the evaporator set to a high pressure.

In order to reduce the power consumption of the compressor to improve the efficiency of the refrigeration cycle (Coefficient of Performance; COP), the ejector needs to significantly increase the pressure of the suction refrigerant and flow out the refrigerant having the increased pressure toward the compressor.

SUMMARY

The present disclosure is directed to providing a refrigeration cycle apparatus including an ejector capable of significantly increasing the pressure of sucked refrigerant and flowing out the refrigerant having the increased pressure toward a compressor, and a refrigerator including the same.

One aspect of the present disclosure provides a refrigeration cycle apparatus including a compressor, a condenser configured to condense a refrigerant compressed in the compressor, a first evaporator configured to evaporate the refrigerant condensed in the condenser, a second evaporator configured to evaporate the refrigerant condensed in the condenser, and an ejector configured to suck a second refrigerant evaporated in the second evaporator by a first refrigerant evaporated in the first evaporator and to discharge the sucked refrigerant toward the compressor, wherein the ejector includes a first inlet configured to allow the first refrigerant to be introduced, a second inlet configured to allow the second refrigerant to be introduced, a joining portion configured to join the first refrigerant introduced through the first inlet and the second refrigerant introduced through the second inlet, a throttle portion formed by reducing a cross-sectional area of a flow passage of the first refrigerant introduced through the first inlet, and a diffuser portion including a cylindrical or conical flow passage upstream of the joining portion to allow the first refrigerant that has passed through the throttle portion to pass therethrough.

An inner angle of the diffuser portion may be 0° or more and 12° or less.

The ejector may further include a parallel portion including a cylindrical flow passage configured such that the first refrigerant and the second refrigerant joined downstream of the joining portion passes therethrough.

An area ratio Sr (Sr=Sm/Se) of a flow passage area Sm of the parallel portion to an outlet area Se of the diffuser portion may be 2.5 or more and 5.6 or less.

A length ratio Lr (Lr=Lm/De) of a length Lm of the parallel portion to a diameter De of the most downstream portion of the diffuser portion may be 14 or less.

The ejector may be configured such that the refrigerant gasified in the first evaporator is introduced through the first inlet as the first refrigerant.

A ratio f (f=De/Llc) of a diameter De of the most downstream portion of the diffuser portion to a distance Llc between an outer end of the most downstream portion of the diffuser portion and an inner end of the most upstream portion of the parallel portion may be 0.82 or more and 1.17 or less.

The ejector may further include a decompression portion formed in a conical shape in which the diameter of a flow passage between the first inlet and the throttle portion is reduced, and the throttle portion may be formed in a circular shape as a boundary between the decompression portion and the diffuser portion.

The throttle portion may include a cylindrical flow passage.

Another aspect of the present disclosure provides a refrigerator that includes a refrigeration cycle apparatus including a compressor, a condenser configured to condense a refrigerant compressed in the compressor, a first evaporator configured to evaporate the refrigerant condensed in the condenser, a second evaporator configured to evaporate the refrigerant condensed in the condenser, and an ejector configured to suck a second refrigerant evaporated in the second evaporator by a first refrigerant evaporated in the first evaporator and to discharge the sucked refrigerant toward the compressor, wherein the ejector includes a first inlet configured to allow the first refrigerant to be introduced, a second inlet configured to allow the second refrigerant to be introduced, a joining portion configured to join the first refrigerant introduced through the first inlet and the second refrigerant introduced through the second inlet, a throttle portion formed by reducing a cross-sectional area of a flow passage of the first refrigerant introduced through the first inlet, and a diffuser portion including a cylindrical or conical flow passage upstream of the joining portion to allow the first refrigerant that has passed through the throttle portion to pass therethrough.

An inner angle of the diffuser portion may be 0° or more and 12° or less.

The ejector may further include a parallel portion including a cylindrical flow passage configured such that the first refrigerant and the second refrigerant joined downstream of the joining portion passes therethrough.

An area ratio Sr (Sr=Sm/Se) of a flow passage area Sm of the parallel portion to an outlet area Se of the diffuser portion may be 2.5 or more and 5.6 or less.

A length ratio Lr (Lr=Lm/De) of a length Lm of the parallel portion to a diameter De of the most downstream portion of the diffuser portion may be 14 or less.

The ejector may be configured such that the refrigerant gasified in the first evaporator is introduced through the first inlet as the first refrigerant.

A ratio f (f=De/Llc) of a diameter De of the most downstream portion of the diffuser portion to a distance Llc between an outer end of the most downstream portion of the diffuser portion and an inner end of the most upstream portion of the parallel portion may be 0.82 or more and 1.17 or less.

The ejector may further include a decompression portion formed in a conical shape in which the diameter of a flow passage between the first inlet and the throttle portion is reduced, and the throttle portion may be formed in a circular shape as a boundary between the decompression portion and the diffuser portion.

The throttle portion may include a cylindrical flow passage.

Another aspect of the present disclosure provides a refrigerator including a first evaporator configured to cool air inside a refrigerating chamber, a second evaporator configured to cool air inside a freezing chamber, an ejector including a nozzle into which a drive refrigerant of a gaseous state evaporated in the first evaporator is introduced, a suction portion into which a suction refrigerant of a gaseous state evaporated in the second evaporator is sucked, a mixing portion in which the drive refrigerant and the suction refrigerant are mixed, and a diffuser configured to boost and flow out the mixed refrigerant, and a compressor into which the mixed refrigerant flowing out of the ejector is introduced, wherein the nozzle includes a decompression portion configured to depressurize the drive refrigerant and including a conical flow passage whose diameter decreases along a flow direction, a circular or cylindrical throttle portion having the smallest cross-sectional area of the flow passage of the drive refrigerant, and a diffuser portion configured to increase the flow speed of the drive refrigerant that has passed through the throttle portion and including a cylindrical or conical flow passage, and wherein the mixing portion includes a joining portion configured to join the drive refrigerant introduced into the nozzle and the suction refrigerant introduced into the suction portion and including a conical flow passage whose diameter increases along a flow direction, and a parallel portion configured to allow the drive refrigerant and the suction refrigerant joined in the joining portion to pass therethrough and including a cylindrical flow passage.

An inner angle of the diffuser portion may be 0° or more and 12° or less, an area ratio Sr (Sr=Sm/Se) of a flow passage area Sm of the parallel portion to an outlet area Se of the diffuser portion may be 2.5 or more and 5.6 or less, a length ratio Lr (Lr=Lm/De) of a length Lm of the parallel portion to a diameter De of the most downstream portion of the diffuser portion may be 14 or less, and a ratio f (f=De/Llc) of a diameter De of the most downstream portion of the diffuser portion to a distance Llc between an outer end of the most downstream portion of the diffuser portion and an inner end of the most upstream portion of the parallel portion may be 0.82 or more and 1.17 or less.

According to the present disclosure, a refrigeration cycle apparatus including an ejector capable of significantly increasing the pressure of the suction refrigerant and flowing out the refrigerant having the increased pressure toward a compressor can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a schematic configuration of a refrigeration cycle apparatus according to an embodiment.

FIG. 2 is a view illustrating a schematic configuration of a refrigerator to which the refrigeration cycle apparatus according to an embodiment is applied.

FIG. 3 is a view illustrating a schematic configuration of an ejector.

FIG. 4 is a graph illustrating a correlation between an angle α and a boosting rate PLR.

FIG. 5A is a view illustrating the flow speed of a refrigerant in a nozzle diffuser portion of a nozzle and a mixing portion when the angle α is 1.5°.

FIG. 5B is a view illustrating the flow speed of the refrigerant in the nozzle diffuser portion of the nozzle and the mixing portion when the angle α is 1.5°.

FIG. 6 is a graph illustrating a correlation between an area ratio Sr and the boosting ratio PLR.

FIG. 7 is a graph illustrating a correlation between a length ratio Lr and the boosting ratio PLR.

FIG. 8 is an enlarged view of a portion VIII of FIG. 3.

FIG. 9 is a graph illustrating a correlation between a ratio f and the boosting rate PLR.

FIG. 10 is a graph illustrating a correlation between the angle α, the ratio f, and the boosting rate PLR.

FIG. 11 is a view illustrating a modification example of the nozzle of the ejector.

SUMMARY

Hereinafter embodiments of the present disclosure are described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating a schematic configuration of a refrigeration cycle apparatus 1 according to an embodiment.

The refrigeration cycle apparatus 1 includes a compressor 10 for compressing a refrigerant, a condenser 20 for condensing the refrigerant compressed by the compressor 10, and a flow control valve 30. In the refrigeration cycle apparatus 1 according to the present embodiment, an R600a refrigerant is used.

The refrigeration cycle apparatus 1 also includes a first expansion device 40 and a first evaporator 50. The refrigeration cycle apparatus 1 also includes a second expansion device 60 and a second evaporator 70. The first expansion device 40 and the second expansion device 60 include an expansion valve or a capillary tube, and decompress and expand the refrigerant flowing out of the condenser 20. The first evaporator 50 and the second evaporator 70 will be described later.

The refrigeration cycle apparatus 1 also includes an ejector 100 configured to suck the refrigerant transferred from the second evaporator 70 by the refrigerant transferred from the first evaporator 50. The ejector 100 will be described later.

The refrigeration cycle apparatus 1 also includes a refrigerant pipe 80 for sequentially connecting the compressor 10, the condenser 20, and the flow control valve 30. The refrigeration cycle apparatus 1 also includes a first branch pipe 81 and a second branch pipe 82 branched from downstream of the flow control valve 30. The first expansion device 40 and the first evaporator 50 are sequentially connected by the first branch pipe 81. The second expansion device 60 and the second evaporator 70 are sequentially connected by the second branch pipe 82. The first branch pipe 81 is connected to a drive refrigerant inlet 111 of the ejector 100, which will be described later, and the second branch pipe 82 is connected to a suction refrigerant inlet 121 of the ejector 100, which will be described later. The refrigeration cycle apparatus 1 also includes a compressed refrigerant pipe 83 for connecting a mixed refrigerant outlet 141 of the ejector 100, which will be described later, and a suction side of the compressor 10.

FIG. 2 is a view illustrating a schematic configuration of a refrigerator 200 to which the refrigeration cycle apparatus 1 according to the present embodiment is applied.

The refrigerator 200 includes a refrigerating chamber 220 to refrigerate food and the like and a freezing chamber 230 to freeze food and the like, which are partitioned in a housing 210 by a partition. The refrigerator 200 also includes a machine room 240 provided in the rear of the freezing chamber 230.

The refrigerator 200 includes a first cold air passage 221 provided in the rear of the refrigerating chamber 220. The first evaporator 50 of the refrigeration cycle apparatus 1 and a refrigerating chamber blower 222 for blowing air into the refrigerating chamber 220 are installed in the first cold air passage 221. The first evaporator 50 evaporates the refrigerant depressurized by the first expansion device 40 by exchanging heat with cold air in the first cold air passage 221. The cold air cooled by heat exchange with the first evaporator 50 is raised in the first cold air passage 221 by the refrigerating chamber blower 222 and is discharged to the refrigerating chamber 220 through a discharge port of the first cold air passage 221, thereby cooling the inside of the refrigerating chamber 220. The evaporation temperature of the first evaporator 50 is adjusted by the first expansion device 40 in order to cool the inside of the refrigerating chamber 220.

The refrigerator 200 includes a second cold air passage 231 provided in the rear of the freezing chamber 230. The second evaporator 70 of the refrigeration cycle apparatus 1 and a freezing chamber blower 232 for blowing air into the freezing chamber 230 are installed in the second cold air passage 231. The second evaporator 70 evaporates the refrigerant depressurized by the second expansion device 60 by exchanging heat with cold air in the second cold air passage 231. The cold air cooled by heat exchange with the second evaporator 70 is raised in the second cold air passage 231 by the freezing chamber blower 232 and is discharged to the freezing chamber 230 through a discharge port of the second cold air passage 231, thereby cooling the inside of the freezing chamber 230. The evaporation temperature of the second evaporator 70 is adjusted by the second expansion device 60 in order to cool the inside of the freezing chamber 230.

The compressor 10 is disposed in the machine room 240.

The condenser 20 is disposed in the machine room 240, at a lower portion of the housing 210 and the like.

The ejector 100 is installed in the first cold air passage 221 or in the second cold air passage 231. However, the ejector 100 may be installed in a wall of a rear portion of the housing 210.

In the refrigeration cycle apparatus 1 configured as described above, a high temperature and high pressure refrigerant compressed by the driving of the compressor 10 is radiated and condensed by the condenser 20. A part of the refrigerant condensed in the condenser 20 is introduced into the ejector 100 via the first expansion device 40 and the first evaporator 50 through the first branch pipe 81. On the other hand, a part of the refrigerant condensed in the condenser 20 is introduced into the ejector 100 via the second expansion device 60 and the second evaporator 70 through the second branch pipe 82. The refrigerant joined in the ejector 100 flows out from the diffuser 140, which will be described later, and is introduced into the compressor 10.

<An Ejector 100>

FIG. 3 is a view illustrating a schematic configuration of the ejector 100.

The ejector 100 includes a nozzle 110 through which the refrigerant (hereinafter referred to as “drive refrigerant”) evaporated in the first evaporator 50 passes, and a suction portion 120 for sucking the refrigerant (hereinafter referred to as “suction refrigerant”) evaporated in the second evaporator 70.

The ejector 100 also includes a mixing portion 130 for mixing the drive refrigerant and the suction refrigerant, and a diffuser 140 for boosting and flowing out the mixed refrigerant mixed in the mixing portion 130.

The nozzle 110 is provided with a drive refrigerant inlet 111 into which the drive refrigerant flows.

The suction portion 120 is provided with the suction refrigerant inlet 121 into which the suction refrigerant flows.

The diffuser 140 is provided with the mixed refrigerant outlet 141 through which the mixed refrigerant flows out.

The nozzle 110 includes a decompression portion 112 for depressurizing the drive refrigerant, a nozzle neck portion 113 having a reduced cross-sectional area of the flow passage of the drive refrigerant, and a nozzle diffuser portion 114 for increasing the flow speed of the drive refrigerant.

The decompression portion 112 has a substantially conical flow passage whose diameter decreases toward the right side in FIG. 3.

The nozzle diffuser portion 114 has a substantially conical flow passage whose diameter increases toward the right side in FIG. 3, or has a substantially cylindrical flow passage whose diameter is the same. The nozzle diffuser portion 114 will be described in detail later.

The nozzle neck portion 113 is the portion having the smallest flow passage area between the decompression portion 112 and the nozzle diffuser portion 114.

The suction portion 120 has a substantially cylindrical flow passage formed around the nozzle 110.

The mixing portion 130 includes a joining portion 131 having a substantially conical flow passage whose diameter increases toward the right side in FIG. 3, and a parallel portion 132 having a substantially cylindrical flow passage whose diameter is the same.

The diffuser 140 has a substantially conical flow passage whose diameter increases toward the right side in FIG. 3.

In the ejector 100 configured as described above, the drive refrigerant, which is a gaseous refrigerant after evaporating (gasified) by heat exchange in the first evaporator 50, that is, which is a refrigerant containing no droplets or a refrigerant containing a small amount of droplets, is introduced through the drive refrigerant inlet 111 of the nozzle 110. In addition, the suction refrigerant, which is a gaseous refrigerant after evaporating (gasified) by heat exchange in the second evaporator 70, that is, which is a refrigerant containing no droplets or a refrigerant containing a small amount of droplets, is introduced into the suction refrigerant inlet 121 of the suction portion 120.

The ejector 100 joins the drive refrigerant introduced into the drive refrigerant inlet 111 and the suction refrigerant introduced into the suction refrigerant inlet 121, in the mixing portion 130 to form a mixed refrigerant, and then flows out the mixed refrigerant through the mixed refrigerant outlet 141.

With this configuration, the drive refrigerant introduced through the drive refrigerant inlet 111 is decompressed and expanded in the decompression portion 112 due to the decrease in the flow passage area. The flow speed of the drive refrigerant increasing by decompression further increases in the nozzle neck portion 113 and then further more increases in the nozzle diffuser portion 114. Accordingly, the ultra-high speed drive refrigerant flows out of the nozzle 110.

The suction refrigerant sucked through the suction refrigerant inlet 121 of the suction portion 120 is sucked into the ultra-high speed drive refrigerant by the pressure difference between the suction refrigerant inlet 121 and an outlet of the nozzle 110. The high speed drive refrigerant flowing out of the outlet of the nozzle 110 and the low speed suction refrigerant begin to mix in the joining portion 131 of the mixing portion 130. Kinetic energy exchange occurs between the drive refrigerant and the suction refrigerant.

Also, due to the deceleration caused by the flow passage enlargement in the diffuser 140, the dynamic pressure is converted to the static pressure, the pressure increases, and the mixed refrigerant flows out through the diffuser 140.

The ejector 100 according to the present embodiment has a function of sucking the suction refrigerant through the suction refrigerant inlet 121 by lowering the static pressure by flowing the drive refrigerant introduced through the drive refrigerant inlet 111 at a high speed. The higher the pressure (hereinafter referred to as “outlet pressure Pc”) of the mixed refrigerant flowing out toward the compressor 10 through the mixed refrigerant outlet 141 of the diffuser 140 with respect to the pressure (hereinafter referred to as “suction pressure Pe”) of the suction refrigerant in the suction refrigerant inlet 121, the higher the performance of the ejector 100. That is, when the value obtained by dividing the outlet pressure Pc by the suction pressure Pe is referred to as a “boosting rate PLR” (the boosting rate PLR=the outlet pressure Pc/the suction pressure Pe), the higher the boosting rate PLR, the higher the performance of the ejector 100. This is because the higher the pressure of the refrigerant introduced into the compressor 10, the more the efficiency (a performance factor COP) of the refrigeration cycle apparatus 1 may be improved.

In the ejector 100 according to the present embodiment as described above, the gaseous refrigerant after evaporating (gasified) by heat exchange in the first evaporator 50 is introduced through the drive refrigerant inlet 111 of the nozzle 110 as the drive refrigerant. When the drive refrigerant introduced through the drive refrigerant inlet 111 of the nozzle 110 is a liquid refrigerant, the nozzle 110 through which the drive refrigerant passes needs to have functions of evaporating the liquid refrigerant and flowing the refrigerant at a high speed. This is because while a part of the liquid refrigerant evaporates to become a gas, the remainder in a droplet state interferes with the speeding up of the refrigerant.

Because the ejector 100 according to the present embodiment is an ejector in which the drive refrigerant is a single phase type (which does not contain droplets or contains a small amount of droplets), the nozzle 110 through which the drive refrigerant passes may increase the boosting rate (PLR) by having a function of increasing the flow speed of the drive refrigerant at a high speed even if the nozzle 110 does not have a function of evaporating the refrigerant.

As a result of a study by the present inventors, it was found that an inner angle α (an angle formed between straight lines L having a cross-sectional shape cut from the surface passing through a center line C of a flow passage outer circumferential surface (an inner circumferential surface of the portion forming the flow passage in the nozzle diffuser portion 114) of the nozzle diffuser portion 114) of the nozzle diffuser portion 114 is appropriately 0° or more and 12° or less.

FIG. 4 is a graph illustrating a correlation between the inner angle α and the boosting rate PLR. FIG. 4 illustrates a correlation when an area ratio Sr, which will be described later, is 3.4 and a length ratio Lr, which will be described later, is 8.0.

FIG. 5A is a view illustrating the flow speed of the refrigerant in the nozzle diffuser portion 114 of the nozzle 110 and the mixing portion 130 when the angle α is 1.5°. FIG. 5B is a view illustrating the flow speed of the refrigerant in the nozzle diffuser portion 114 of the nozzle 110 and the mixing portion 130 when the angle α is 1.5°. FIGS. 5A and 5B illustrates that the higher the flow speed of the refrigerant, the finer the hatching. The finest hatching represents the supersonic speed. In FIGS. 5A and 5B, hatching indicating the cross section of the nozzle 110 is omitted.

When the angle α is 15°, because the drive refrigerant is about to flow along an inner circumferential surface of the nozzle diffuser portion 114 but is pushed by the suction refrigerant, separation occurs in the nozzle diffuser portion 114, resulting in loss. Accordingly, as illustrated in FIG. 5B, the flow speed at a flow passage outlet 114 a of the nozzle diffuser portion 114 decreases. When the flow speed decreases, the static pressure increases, and the force to suck the suction refrigerant decreases. As a result, the boosting rate PLR decreases, so that the efficiency of the refrigeration cycle apparatus 1 becomes difficult to increase.

In contrast, as illustrated in FIG. 5A, when the angle α is 1.5°, because the flow speed of the drive refrigerant flowing along the inner circumferential surface of the nozzle diffuser portion 114 is fast and thus no separation occurs in the nozzle diffuser portion 114, no decrease in flow speed occurs. In addition, because the flow speed at the flow passage outlet 114 a of the nozzle diffuser portion 114 is fast, the static pressure decreases, and the force to suck the suction refrigerant increases. As a result, the boosting rate PLR increases, so that the efficiency of the refrigeration cycle apparatus 1 becomes easy to increase.

As a result of a study by the present inventors, it was found that as illustrated in FIG. 4, when the angle α is 0° or more and 12° or less, the boosting rate PLR becomes 1.15 or more, so that the boosting rate PLR is larger than in a case where the angle α is larger than 12°. Accordingly, by making the angle α into 0° or more and 12° or less, the performance of the ejector 100 may be further improved than in the case where the angle α is larger than 12°. As a result, by making the angle α into 0° or more and 12° or less, the efficiency (the performance factor COP) of the refrigeration cycle apparatus 1 may be improved rather than in the case where the angle α is larger than 12°.

It is further appropriate that the angle α is 0° or more and 9.5° or less. When the angle α is 0° or more and 9.5° or less, the boosting rate PLR becomes 1.20 or more, so that the boosting rate PLR is larger than in a case where the angle α is larger than 9.5°. It is particularly appropriate that the angle α is 1.5° or more and 4° or less. When the angle α is 1.5° or more and 4° or less, the boosting rate PLR becomes 1.225 or more, so that the boosting rate PLR is larger than in a case where the angle α is 0° or more and 1.5° or less, and larger than 4°.

As a result of a study by the present inventors, it was found that it is appropriate that the area ratio Sr (Sr=a parallel portion area Sm/an outlet area Se) of the parallel portion area Sm (refer to FIG. 3), which is the flow passage area of the parallel portion 132 of the mixing portion 130, to the outlet area Se (refer to FIG. 3), which is the area of the flow passage outlet 114 a of the nozzle diffuser portion 114, is 2.5 or more and 5.6 or less.

FIG. 6 is a graph illustrating a correlation between the area ratio Sr and the boosting ratio PLR. FIG. 6 illustrates a correlation when the angle α is 1.5° and the length ratio Lr is 8.0.

As illustrated in FIG. 6, when the area ratio Sr is 2.5 or more and 5.6 or less, the boosting rate PLR becomes 1.15 or more, so that the boosting rate PLR is larger than in a case where the area ratio Sr is smaller than 2.5 and in a case where the area ratio Sr is larger than 5.6.

When the ratio of the parallel portion area Sm of the parallel portion 132 of the mixing portion 130 to the outlet area Se of the flow passage outlet 114 a of the nozzle diffuser portion 114 is excessively small, the space to suck the suction refrigerant is small and the force to suck the suction refrigerant decreases, so that the boosting rate PLR becomes decreases.

On the other hand, when the ratio of the parallel portion area Sm of the parallel portion 132 of the mixing portion 130 to the outlet area Se of the flow passage outlet 114 a of the nozzle diffuser portion 114 is excessively large, because the space to suck the suction refrigerant becomes large and the drive refrigerant and the suction refrigerant become difficult to exchange kinetic energy, the force to suck the suction refrigerant decreases.

As a result, when the area ratio Sr is smaller than 2.5 and the area ratio Sr is larger than 5.6, the boosting rate PLR decreases, so that the efficiency of the refrigeration cycle apparatus 1 becomes difficult to increase.

In contrast, when the area ratio Sr is 2.5 or more and 5.6 or less, because the space to suck the suction refrigerant may be secured and the drive refrigerant and the suction refrigerant may exchange kinetic energy, the force to suck the suction refrigerant increases. As a result, the boosting rate PLR increases and the efficiency of the refrigeration cycle apparatus 1 increases.

Accordingly, by making the area ratio Sr into 2.5 or more and 5.6 or less, the performance of the ejector 100 may be further improved than in the case where the area ratio Sr is smaller than 2.5 and in the case where the area ratio Sr is larger than 5.6. As a result, by making the area ratio Sr into 2.5 or more and 5.6 or less, the efficiency of the refrigeration cycle apparatus 1 may be further improved than in the case where the area ratio Sr is smaller than 2.5 and in the case where the area ratio Sr is larger than 5.6.

It is further appropriate that the area ratio Sr is 2.8 or more and 4.3 or less. When the area ratio Sr is 2.8 or more and 4.3 or less, the boosting rate PLR becomes 1.20 or more, so that the boosting rate PLR is larger than in a case where the area ratio Sr is smaller than 2.8 and in a case where the area ratio Sr is larger than 4.3. Accordingly, by making the area ratio Sr into 2.8 or more and 4.3 or less, the efficiency of the refrigeration cycle apparatus 1 may be improved.

As a result of a study by the present inventors, it was found that it is appropriate that the length ratio Lr (Lr_=a parallel portion length Lm/an outlet diameter De) of the parallel portion length Lm (refer to FIG. 3), which is a length of the parallel portion 132 of the mixing portion 130 in the centerline direction, to the outlet diameter De (refer to FIG. 3), which is a diameter of the flow passage outlet 114 a (the most downstream) of the nozzle diffuser portion 114, is 14 or less.

FIG. 7 is a graph illustrating a correlation between the length ratio Lr and the boosting ratio PLR. FIG. 7 illustrates a correlation when the angle α is 1.5° and the area ratio Sr is 3.4.

As illustrated in FIG. 7, when the length ratio Lr is 14 or less, the boosting ratio PLR becomes 1.1 or more, so that the boosting ratio PLR is larger than in a case where the length ratio Lr is larger than 14.

When the length ratio Lr of the parallel portion length Lm of the parallel portion 132 of the mixing portion 130 to the outlet diameter De of the flow passage outlet 114 a of the nozzle diffuser portion 114 is excessively large (when the length ratio Lr is larger than 14), it is considered that the boosting rate PLR becomes small because the pressure loss in the parallel portion 132 of the mixing portion 130 becomes large and the flow speed of the refrigerant decreases.

In contrast, when the length ratio Lr is 14 or less, the pressure loss in the parallel portion 132 of the mixing portion 130 is small, the flow speed of the refrigerant increases, and the static pressure decreases. As a result, the force to suck the suction refrigerant increases. Also, because the drive refrigerant and the suction refrigerant may perform kinetic energy exchange in the parallel portion 132 of the mixing portion 130, the force to suck the suction refrigerant is improved.

Accordingly, by making the length ratio Lr into 14 or less, the boosting ratio PLR may be increased more than in the case where the length ratio Lr is larger than 14, and the performance of the ejector 100 may be improved. As a result, by making the length ratio Lr into 14 or less, the efficiency of the refrigeration cycle apparatus 1 may be further improved than in the case where the length ratio Lr is larger than 14.

It is further appropriate that the length ratio Lr is 3.0 or more and 12.5 or less. When the length ratio Lr is 3.0 or more and 12.5 or less, the boosting rate PLR becomes 1.20 or more, so that the boosting rate PLR is larger than in a case where the length ratio Lr is smaller than 3.0 and in a case where the length ratio Lr is larger than 12.5. Accordingly, by making the length ratio Lr into 3.0 or more and 12.5 or less, the efficiency of the refrigeration cycle apparatus 1 may be improved.

<Regarding the Shape of the Joining Portion 131>

FIG. 8 is an enlarged view of a portion VIII of FIG. 3.

The joining portion 131 of the mixing portion 130 is a space between the nozzle 110 and the parallel portion 132 of the mixing portion 130 in the centerline direction. Also, the joining portion 131 is a space in a curved surface Cs that linearly connects an outer end 110 a of the outlet of the nozzle 110 and an inner end 132 a of the inlet of the parallel portion 132 in a radial direction. The shape of the cross section obtained by cutting the curved surface Cs from a surface passing through the center line C becomes a straight line Lc shown by broken lines in FIG. 8. Also, the curved surface Cs is a surface showing the boundary between the suction portion 120 and the joining portion 131, and at the same time is an outlet through which the suction refrigerant flows out from the suction portion 120.

As a result of a study by the present inventors, it was found that it is appropriate that a ratio f (f=the outlet diameter De/a length Llc) of the outlet diameter De of the nozzle diffuser portion 114 of the nozzle 110 to the length Llc (the distance between the end 110 a of the nozzle 110 and the end 132 a of the parallel portion 132) of the straight line Lc is 0.82 or more and 1.17 or less.

FIG. 9 is a graph illustrating a correlation between the ratio f and the boosting rate PLR.

As illustrated in FIG. 9, when the ratio f is 0.82 or more and 1.17 or less, the boosting rate PLR becomes 1.15 or more, so that the boosting rate PLR is larger than in a case where the ratio f is smaller than 0.82 and in a case where the ratio f is larger than 1.17.

When the ratio f of the outlet diameter De of the nozzle diffuser portion 114 to the length Llc of the straight line Lc is excessively small, because the space to suck the suction refrigerant becomes large and the drive refrigerant and the suction refrigerant become difficult to exchange kinetic energy, the force to suck the suction refrigerant decreases.

On the other hand, when the ratio f of the outlet diameter De of the nozzle diffuser portion 114 to the length Llc of the straight line Lc is excessively large, because the space to suck the suction refrigerant is small and the force to suck the suction refrigerant decreases, the boosting rate PLR decreases.

As a result, when the ratio f is smaller than 0.82 and is larger than 1.17, the boosting rate PLR decreases, so that the efficiency of the refrigeration cycle apparatus 1 becomes difficult to increase.

In contrast, when the ratio f is 0.82 or more and 1.17 or less, because the space to suck the suction refrigerant may be secured and the kinetic energy exchange between the drive refrigerant and the suction refrigerant is facilitated, the force to suck the suction refrigerant increases. As a result, the boosting rate PLR increases and the efficiency of the refrigeration cycle apparatus 1 increases.

Accordingly, by making the ratio f into 0.82 or more and 1.17 or less, the performance of the ejector 100 may be further improved than in the case where the ratio f is smaller than 0.82 and in the case where the ratio f is larger than 1.17. As a result, by making the ratio f into 0.82 or more and 1.17 or less, the efficiency of the refrigeration cycle apparatus 1 may be further improved than in the case where the ratio f is smaller than 0.82 and in the case where the ratio f is larger than 1.17.

It is further appropriate that the ratio f is 0.85 or more and 1.12 or less. When the ratio f is 0.85 or more and 1.12 or less, the boosting rate PLR becomes 1.20 or more, so that the boosting rate PLR is larger than in the case where the ratio f is smaller than 0.85 and in the case where the ratio f is larger than 1.12. Accordingly, by making the ratio f into 0.85 or more and 1.12 or less, the efficiency of the refrigeration cycle apparatus 1 may be improved.

FIG. 10 is a graph illustrating a correlation between the angle α, the ratio f, and the boosting rate PLR.

When the length Llc of the straight line Lc is the same, because the outlet diameter De of the nozzle diffuser portion 114 of the nozzle 110 becomes larger as the angle α becomes larger, as illustrated in FIG. 10, the ratio f becomes larger as the angle α becomes larger. In this way, the ratio f changes depending on the angle α. Also, because the outlet area Se becomes larger as the outlet diameter De becomes larger and the area ratio Sr becomes smaller as the outlet area Se becomes larger, the ratio f becomes larger as the area ratio Sr becomes smaller. In this way, the ratio f changes depending on the area ratio Sr. Also, because the length ratio Lr becomes smaller as the outlet diameter De becomes larger, the ratio f becomes larger as the length ratio Lr becomes smaller. In this way, the ratio f changes depending on the length ratio Lr.

As described above, the ejector 100 includes the drive refrigerant inlet 111 as an example of a first inlet for allowing the drive refrigerant as an example of a first refrigerant to be introduced, and the suction refrigerant inlet 121 as an example of a second inlet for allowing the suction refrigerant as an example of a second refrigerant to be introduced. The ejector 100 also includes the joining portion 131 for allowing the drive refrigerant introduced through the drive refrigerant inlet 111 and the suction refrigerant introduced through the suction refrigerant inlet 121 to join, and the parallel portion 132 having a cylindrical flow passage downstream of the joining portion 131 for allowing the joined drive refrigerant and suction refrigerant to pass therethrough. The ejector 100 also includes the nozzle neck portion 113 as an example of a throttle portion for reducing the cross-sectional area of the flow passage of the drive refrigerant introduced through the drive refrigerant inlet 111, and the nozzle diffuser portion 114 as an example of a diffuser having a cylindrical or conical flow passage upstream of the joining portion 131 for allowing the drive refrigerant that has passed through the nozzle neck portion 113 to pass therethrough. Also, in the ejector 100, the ratio f as an example of a ratio of the outlet diameter De of the most downstream portion of the nozzle diffuser portion 114 to the distance (the length Llc) between the end 110 a as an example of an outer end at the most downstream portion of the nozzle diffuser portion 114 and the end 132 a as an example of an inner end at the most upstream portion of the parallel portion 132 is 0.82 or more and 1.17 or less. According to the ejector 100 configured as described above, compared to the case where the ratio f is smaller than 0.82 or the ratio f is larger than 1.17, the performance of the ejector 100 may be improved. As a result, the efficiency of the refrigeration cycle apparatus 1 including the ejector 100 may be improved.

<A Modification Example of the Nozzle 110 of the Ejector 100>

FIG. 11 is a view illustrating a modification example of the nozzle 110 of the ejector 100.

In the above-described embodiment, the nozzle neck portion 113 of the nozzle 110 has a circular shape as a boundary between the substantially conical flow passage in the decompression portion 112 and the substantially conical flow passage in the nozzle diffuser portion 114, the present disclosure is not particularly limited to this shape. As illustrated in FIG. 11, the nozzle neck portion 113 may have a substantially cylindrical flow passage having the same diameter. 

1. A refrigeration cycle apparatus comprising: a compressor; a condenser configured to condense a refrigerant compressed in the compressor; a first evaporator configured to evaporate the refrigerant condensed in the condenser; a second evaporator configured to evaporate the refrigerant condensed in the condenser; and an ejector configured to suck a second refrigerant evaporated in the second evaporator by a first refrigerant evaporated in the first evaporator and to discharge the sucked refrigerant toward the compressor, wherein the ejector includes: a first inlet configured to allow the first refrigerant to be introduced; a second inlet configured to allow the second refrigerant to be introduced; a joining portion configured to join the first refrigerant introduced through the first inlet and the second refrigerant introduced through the second inlet; a throttle portion in which a cross-sectional area of a flow passage of the first refrigerant introduced through the first inlet is reduced; and a diffuser portion including a cylindrical or conical flow passage upstream of the joining portion to allow the first refrigerant that has passed through the throttle portion to pass therethrough.
 2. The refrigeration cycle apparatus according to claim 1, wherein an inner angle of the diffuser portion is 0 degrees or more and 12 degrees or less.
 3. The refrigeration cycle apparatus according to claim 1, wherein the ejector further includes a parallel portion including a cylindrical flow passage configured such that the first refrigerant and the second refrigerant joined downstream of the joining portion pass therethrough.
 4. The refrigeration cycle apparatus according to claim 3, wherein an area ratio Sr (Sr=Sm/Se) of a flow passage area Sm of the parallel portion to an outlet area Se of the diffuser portion is 2.5 or more and 5.6 or less.
 5. The refrigeration cycle apparatus according to claim 3, wherein a length ratio Lr (Lr=Lm/De) of a length Lm of the parallel portion to a diameter De of the most downstream portion of the diffuser portion is 14 or less.
 6. The refrigeration cycle apparatus according to claim 1, wherein the ejector is configured such that the refrigerant gasified in the first evaporator is introduced through the first inlet as the first refrigerant.
 7. The refrigeration cycle apparatus according to claim 3, wherein a ratio f (f=De/Llc) of a diameter De of the most downstream portion of the diffuser portion to a distance Llc between an outer end of the most downstream portion of the diffuser portion and an inner end of the most upstream portion of the parallel portion is 0.82 or more and 1.17 or less.
 8. The refrigeration cycle apparatus according to claim 1, wherein the ejector further includes a decompression portion formed in a conical shape in which the diameter of a flow passage between the first inlet and the throttle portion is reduced, and the throttle portion is formed in a circular shape as a boundary between the decompression portion and the diffuser portion.
 9. The refrigeration cycle apparatus according to claim 1, wherein the throttle portion includes a cylindrical flow passage.
 10. A refrigerator comprising a refrigeration cycle apparatus including: a compressor; a condenser configured to condense a refrigerant compressed in the compressor; a first evaporator configured to evaporate the refrigerant condensed in the condenser; a second evaporator configured to evaporate the refrigerant condensed in the condenser; and an ejector configured to suck a second refrigerant evaporated in the second evaporator by a first refrigerant evaporated in the first evaporator and to discharge the sucked refrigerant toward the compressor, wherein the ejector includes: a first inlet configured to allow the first refrigerant to be introduced; a second inlet configured to allow the second refrigerant to be introduced; a joining portion configured to join the first refrigerant introduced through the first inlet and the second refrigerant introduced through the second inlet; a throttle portion in which a cross-sectional area of a flow passage of the first refrigerant introduced through the first inlet is reduced; and a diffuser portion including a cylindrical or conical flow passage upstream of the joining portion to allow the first refrigerant that has passed through the throttle portion to pass therethrough.
 11. The refrigerator according to claim 10, wherein an inner angle of the diffuser portion is 0 degrees or more and 12 degrees or less.
 12. The refrigerator according to claim 10, wherein the ejector further includes a parallel portion including a cylindrical flow passage configured such that the first refrigerant and the second refrigerant joined downstream of the joining portion pass therethrough.
 13. The refrigerator according to claim 12, wherein an area ratio Sr (Sr=Sm/Se) of a flow passage area Sm of the parallel portion to an outlet area Se of the diffuser portion is 2.5 or more and 5.6 or less.
 14. The refrigerator according to claim 12, wherein a length ratio Lr (Lr=Lm/De) of a length Lm of the parallel portion to a diameter De of the most downstream portion of the diffuser portion is 14 or less.
 15. The refrigerator according to claim 10, wherein the ejector is configured such that the refrigerant gasified in the first evaporator is introduced through the first inlet as the first refrigerant.
 16. The refrigerator according to claim 12, wherein a ratio f (f=De/Llc) of a diameter De of the most downstream portion of the diffuser portion to a distance Llc between an outer end of the most downstream portion of the diffuser portion and an inner end of the most upstream portion of the parallel portion is 0.82 or more and 1.17 or less.
 17. The refrigerator according to claim 10, wherein the ejector further includes a decompression portion formed in a conical shape in which the diameter of a flow passage between the first inlet and the throttle portion is reduced, and the throttle portion is formed in a circular shape as a boundary between the decompression portion and the diffuser portion.
 18. The refrigerator according to claim 10, wherein the throttle portion includes a cylindrical flow passage.
 19. A refrigerator comprising a first evaporator configured to cool air inside a refrigerating chamber; a second evaporator configured to cool air inside a freezing chamber; an ejector including a nozzle into which a drive refrigerant of a gaseous state evaporated in the first evaporator is introduced, a suction portion into which a suction refrigerant of a gaseous state evaporated in the second evaporator is sucked, a mixing portion in which the drive refrigerant and the suction refrigerant are mixed, and a diffuser configured to boost and flow out the mixed refrigerant; and a compressor into which the mixed refrigerant flowing out of the ejector is introduced, wherein the nozzle includes: a decompression portion configured to depressurize the drive refrigerant and including a conical flow passage whose diameter decreases along a flow direction; a circular or cylindrical throttle portion having the smallest cross-sectional area of the flow passage of the drive refrigerant; and a diffuser portion configured to increase the flow speed of the drive refrigerant that has passed through the throttle portion and including a cylindrical or conical flow passage, and wherein the mixing portion includes: a joining portion configured to join the drive refrigerant introduced into the nozzle and the suction refrigerant introduced into the suction portion and including a conical flow passage whose diameter increases along a flow direction; and a parallel portion configured to allow the drive refrigerant and the suction refrigerant joined in the joining portion to pass therethrough and including a cylindrical flow passage.
 20. The refrigerator according to claim 19, wherein an inner angle of the diffuser portion is 0 degrees or more and 12 degrees or less, an area ratio Sr (Sr=Sm/Se) of a flow passage area Sm of the parallel portion to an outlet area Se of the diffuser portion is 2.5 or more and 5.6 or less, a length ratio Lr (Lr=Lm/De) of a length Lm of the parallel portion to a diameter De of the most downstream portion of the diffuser portion is 14 or less, and a ratio f (f=De/Llc) of a diameter De of the most downstream portion of the diffuser portion to a distance Llc between an outer end of the most downstream portion of the diffuser portion and an inner end of the most upstream portion of the parallel portion is 0.82 or more and 1.17 or less. 